The present invention relates to the field of steering columns for automotive vehicles, and specifically to a collapsible, energy and motion distributing steering column.
Steering columns in automotive vehicles typically comprise axially extending cylindrical bodies, with shafts or other linkage elements therein extending from the vehicle steering gear or linkage upwardly and rearwardly to the steering wheel. In the event of a front end collision, the steering linkage and forward end of the steering column shaft may be almost instantaneously rammed rearwardly, directly into the head and/or chest of the driver. In this and other collision scenarios, where there is no steering-wheel-mounted airbag, a driver not wearing a seatbelt could also be catapulted forward into the steering wheel with often critical or fatal results.
Attempts have been made to cushion the impact between the driver and the steering wheel in a collision situation, such as the steering-wheel-mounted airbag. U.S. Pat. No. 4,867,003 to Beauch et al. shows another approach where the steering column includes roll deforming steel balls juxtaposed between cylindrically overlapping, ball-engaging sleeves of the column so that, in the event of a significant forward impact against the steering wheel, the upper column sleeve breaks from its bolted connection to the instrument panel and telescopically collapses. Resistance to the collapse is incurred by friction between the telescopic sleeves and the balls therebetween.
A collapsible steering column is disclosed for use in an automotive vehicle having steering linkage, an instrument panel and a steering wheel. The collapsible steering column includes an upper sleeve having an axis and defining a rearwardly opening cavity and a rear end configured for connection to a steering wheel, the cavity having a rear wall; a lower shaft having an axis and a forward end configured for connection to vehicle steering linkage and having an upper end extending coaxially at least partially within the cavity; a spring disposed within the cavity between the shaft and the rear wall of the cavity; a mating configuration between the sleeve and the shaft for causing the sleeve and the shaft to rotate as a unit about their common axes; and, a detent assembly connected with the sleeve and the vehicle instrument panel for holding the sleeve conditionally against axial movement unless sufficient axial force is applied to the sleeve.